The application relates to a safety belt system for a motor vehicle.
A safety belt system is known from DE 4 232 160 (incorporated by reference herein), comprising a safety belt extending in a direction of extension of the belt, a buckle element arranged in the region of a buckle for deflecting the safety belt in the direction of extension of the belt, the buckle element subdividing the safety belt into a shoulder portion (shoulder belt) extending diagonally over the upper body of a person and a further belt portion connected to the shoulder portion which, in particular in the form of a lap portion (lap belt), extends over the lap of said person strapped-in according to requirements by means of the safety belt, as well as a mobile region of the buckle element which in the event of a dangerous situation (in the event of a crash) may be moved from an initial position in which the safety belt may slide along on the mobile region into a final position in which the safety belt is secured to the buckle element.
In the present application, the phrase “securing the safety belt to the buckle element” is understood as the fixing of the safety belt to the buckle element such that the safety belt may no longer slide along the buckle element and/or only by applying considerably greater, predeterminable forces.
In this application, “direction of extension of the belt” is understood as the direction which the safety belt follows along its entire path, i.e. the direction of extension of the belt alters its orientation three-dimensionally when the safety belt is deflected, for example, by the buckle element.
A drawback with the aforementioned safety belt system is that, in the event of restraint, the force introduced via the safety belt to a vehicle passenger increases in the direction of extension of the belt. Thus with a shoulder portion (shoulder belt) which extends in the direction of extension of the belt from a shoulder belt deflection element diagonally over the upper body of the passenger to the buckle element, the force which acts in the direction of extension of the belt increases and as a result the force introduced into the upper body of the vehicle passenger increases, proceeding from the shoulder of the passenger in the direction of extension of the belt to the chest of the passenger, and namely as a result of the friction between the passenger and the shoulder belt. Consequently, greater forces are applied in the chest region of the vehicle passenger which is susceptible to injury, than on the shoulder region of the vehicle passenger which is relatively less susceptible to injury.
A safety belt system is known from WO 2006/092206 A1 (incorporated by reference herein) in which, moreover, the mobile region is configured by a force acting on the shoulder portion which tensions the shoulder portion in the direction of extension of the belt, to be displaced from its initial position into its final position, the mobile region relieving the shoulder portion when moving into its final position such that the force acting in the direction of extension of the belt of the shoulder portion and thus the resulting force acting on the shoulder portion is limited. In this connection, the mobile region in the form of a first slide for fixing the safety belt to the buckle element drives a separate clamping element in the form of a second slide which clamps the safety belt to the buckle element before the first slide has reached its final position.